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Vibrant Sepehr

#3997df
Notes

Vibrant Sepehr (#3997DF) is a true azure with a vibrant character. It holds its own as a focal accent, carrying visual weight without tipping into neon territory. Its HSL profile (206°, 72%, 55%) places it in the balanced band at a mid lightness. It works across type, buttons, and borders, saturated enough to feel deliberate but balanced enough to not fight the rest of the palette. For a confident two-color system, pair it with its complementary orange. For something softer, pull in its analogous neighbors on either side of the wheel.

HEX
#3997df
RGB
rgb(57, 151, 223)
HSL
hsl(206, 72%, 55%)
HWB
hwb(206 22% 13%)
OKLCH
oklch(65.4% 0.138 245.6)
HSV
hsv(206, 74%, 87%)
LAB
lab(60.18% -3.52 -44.40)
LCH
lch(60.18% 44.54 265.47)
CMYK
cmyk(74%, 32%, 0%, 13%)

Etymology

Vibrant
adjective

From the Latin vibrare, to shake — used as a color word since the seventeenth century for hues that read as alive and resonant. Vibrant orange, vibrant green: the implication is saturation combined with the optical impression of slight motion or energy. Sits at the bright-bucket center alongside vivid and lively.

Sepehr
noun

The Persian word for firmament or celestial sphere — used in Persian Sufi poetry for the cosmic blue beyond the visible sky. Sepehr names the Persian astronomical concept of the seven heavens. The color refers to the Persian Sufi notion of sepehr-e jadid: a saturated, slightly cool very deep blue with the optical depth of upper-atmospheric scattering.

Closest matches

The nearest named color in three reference sources, ranked by perceptual distance (ΔE76 in CIELAB). ΔE < 1 is imperceptible to most viewers; ΔE > 10 is clearly different. When two sources point to the same hex they’re merged into one tile; click any to open that color’s page.

Variations

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Harmonies

Accessibility

Color-vision simulation

How this color appears to viewers with the four major color-vision-deficiency types. Computed via the Machado (2009) physiologically-based model. If a tile matches the original, the color reads the same to that viewer.

#3997df
Original
#769ae2
Protanopia
#5e8ade
Deuteranopia
#00a8b1
Tritanopia
#888888
Achromatopsia
WCAG contrast

The color used as foreground text against pure white and pure black, with the contrast ratio and WCAG 2.1 grade. Aim for AA (4.5:1) for body text and AA Large (3:1) for 18 pt+ headlines; AAA (7:1) is the gold standard for long-form reading surfaces.

The quick brown foxSample body text at normal size. The wcag minimum for body contrast is 4.5:1 (AA) or 7:1 (AAA).
AA Largeon White
3.15:1
The quick brown foxSample body text at normal size. The wcag minimum for body contrast is 4.5:1 (AA) or 7:1 (AAA).
AAon Black
6.67:1

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